1. Field of the Invention
The present invention relates to a receiver provided in a mobile station and a method thereof, and more particularly to an apparatus and method for allowing a mobile station to identify and indicate types of base stations.
2. Description of the Related Art
A mobile communication system based on a code division multiple access (CDMA) system has developed from a voice communication system based on a conventional mobile communication standard into a voice and high-speed data communication system based on an international mobile telecommunication-2000 (IMT-2000) standard. The IMT-2000 system can provide communication services for high-quality voice, moving pictures and Internet searches. In the CDMA mobile communication system, communication links are classified into a forward link directed to a mobile station from a base station and a reverse link directed to a base station from a mobile station.
The conventional CDMA mobile communication system can provide a voice communication service, but cannot appropriately provide a data communication service requiring a high-speed transmission rate and high speech quality.
To provide various multimedia data services such as data communications containing packet data communications other than voice communications, high-quality voice communications, etc., the CDMA mobile communication system must include service channels for providing voice and data communications, and dynamically assign a channel according to a user's request. In this case, a base station subsystem must be able to support voice and data communication services. Here, the base station subsystem is referred to as a CDMA 1X base station subsystem.
Moreover, research for providing a CDMA mobile communication system (hereinafter, referred to as a “CDMA system”) capable of transmitting high-speed data has recently been conducted. A representative communication system having a channel structure for transmitting high-speed data is a high data rate (HDR) system. The HDR system is a mobile communication system for a standard of an HDR system proposed in 3rd generation partnership project 2 (3GPP2) to improve a data communication service provided by an IS-2000 system.
The HDR system uses link adaptation techniques for changing a coding rate and a modulation scheme according to a channel state, and adjusting a data transmission rate. In the forward link of the HDR system, a pilot channel, a forward media access control (MAC) channel, a forward traffic channel and a forward control channel are transmitted after time division multiplexing (TDM) is applied. The forward traffic channel using the link adaptation techniques can implement a transmission operation on the basis of three modulation schemes such as quadrature phase shift keying (QPSK), 8-ary phase shift keying (8PSK) and 16-ary quadrature amplitude modulation (16QAM), three coding rates such as ¼, ⅜ and ½ coding rates, and data transmission rates according to thirteen transmission methods based on a combination of slots in which packets are repeatedly transmitted. In this case, a base station subsystem for supporting only a data communication service is referred to as a CDMA 1X evolution data only (EVDO) base station subsystem.
Where different types of base station subsystems are used, the user must hold different mobile stations according to the different base station subsystems. That is, channel structures are different according to the type of base stations. The mobile station is independently used according to the types of the base stations. An IMT-2000 CDMA system is based on a CDMA standard for North America and a universal mobile telecommunications system (UMTS) standard for Europe.
Mobile stations capable of communicating with the CDMA 1X base station subsystem and the EVDO base station subsystem have been developed. In the future, when full-scaled CDMA communication services are provided, the mobile stations capable of communicating with a CDMA base station subsystem based on a North American standard and a UTMS base station subsystem based on a European standard will be developed. Where a mobile station capable of communicating with at least two different types of base station subsystems is used, the user must be able to identify the type of the base station subsystem to be communicated with in a place where the mobile station is currently located.